In 1947, Darnell won the starring role in the highly anticipated film adaptation when the original star, newcomer Peggy Cummins, proved too inexperienced for the role. The character Amber in the novel was so called because of her eye color. Publicity at the time compared the novel Forever Amber to Gone with the Wind. The search for the actress to portray Amber, a beauty who uses men to make her fortune in 17th-century England, was modeled on the extensive process that led to the casting of Vivien Leigh as Scarlett O'Hara.

The film begins in 1644 during the English Civil War, as we see a group of Roundheads pursuing a Cavalier's carriage. The carriage drives into the country where its passengers abandon a baby, named Amber, on the doorstep of a farming cottage. The roundheads soon catch up with the carriage and kill all the passengers while the farmers discover and decide to adopt Amber.

The film moves forward to 1660; the death of Oliver Cromwell and the restoration of the Monarchy.The residents of London rejoice and celebrate the return of the monarchy. However the small rural towns and villages remain strictly puritanical. Sixteen years after being abandoned in a small rural village, we see that Amber has grown into a beauty and is about to be married despite her protests. She wants to be more than a farmer’s wife and dreams of court fashions and a life away from the village. Her dream comes true with the arrival of a group of cavaliers and the handsome Bruce Carlton, with whom she becomes instantly smitten. She follows the Cavaliers to a tavern and begs Bruce to let her come with him to London. Despite her request and coaxing from Bruce’s friend Almsbury, Bruce refuses her, while Almsbury also unsuccessfully tries to seduce her. Amber once again tries to convince Bruce to take her to London, which he refuses, before they share a kiss.

Bruce and Almsbury return to London to seek an audience with the king but are turned away. Barbra Palmer, the king’s mistress, is brought to court and coldly walks past them. As Bruce and Almsbury return to their London tavern, they see that Amber has followed them to London. Bruce allows her to stay with him and they begin an affair whereby Bruce pampers Amber with new gowns and takes her to the theater. At one performance, Bruce sees Barbra Palmer alone and goes to speak with her about getting the king to grant him ships for his privateer mission. Amber is distraught at the thought of Bruce leaving and stops Almsbury from warning Bruce that the king has arrived. The king sees Bruce with his mistress and later summons him to court.

Not wanting his friend to face the king’s wrath alone, Almsbury goes with him. The king, however, grants Bruce the ships he needs and requests that he leave for Bristol that very night. Bruce and Almsbury return to the tavern to see Amber sleeping. Bruce plans on leaving before Amber wakes, and Almsbury helps him pack, despite telling Bruce that Amber loves him and it would be cruel. The next morning Amber wakes up to find Almsbury packing up his belongings and returning to Almsbury Hall. Almsbury explains that the king gave him back his lands and gave Bruce his ships as Amber races into Bruce’s room to see it empty. Almsbury tries to convince Amber to go back to her village but she refuses, stating that she will marry Bruce no matter what. Almsbury leaves her and gives her money from Bruce to keep her from starving.

However Amber is quickly conned out of her money, put in debt and sent to Newgate Prison. While in Newgate Prison, Amber discovers she’s pregnant with Bruce’s child and meets Black Jack Mallet, a highwayman, who falls in love with her and who helps her break out. The pair go to Mother Redcap’s tavern where Amber gives birth to a son. Amber soon begins to make a living luring fops into alleyways where Black Jack robs them. During one of the robberies, Black Jack is killed by the king’s guard and Amber flees. She hides inside a house where she is discovered by Captain Rex Morgan.

He gets her work as an actress to save her from being sent to Tyburn and takes her as his mistress. While working as an actress, the Earl of Radcliffe shows an interest in Amber, and Almsbury returns to London. He is now married with a child and tells Amber that Bruce will return any day now. Captain Morgan also proposes to Amber but she rejects him because she still loves Bruce.

^'Forever Amber' or 'Crime Doesn't Pay': In the Hollywood version the moral lesson will be underscored; Amber will suffer for her sins. By Frank S. Nugent. New York Times (1923-Current file) [New York, N.Y] 04 Aug 1946: 93.